Previous research from the investigator's laboratory has focused primarily on the electrical activity of the olfactory receptor neurons. As a result of this research it has become increasingly clear that other cells in the olfactory sensory mucosa may influence the activity of the receptor neurons. These cells are the sustentacular cells and the acinar cells of Bowman's glands. They are generally called secretory cells, although this designation should not rule out other possible functions. For example, sustentacular cells may form a network for intercellular communication within the sensory epithelium as well as participate in the uptake and transport of molecules from the superficial mucus and the blood vascular system. It is the specific aim of the proposed experiments to investigate the properties of these largely-ignored and poorly-understood cells. The short-term objectives are: a. to induce secretion in the sustentacular cells and the acinar cells of Bowan's gland by the application of certain critically selected odorants and pharmacological reagents, b. to study the changes in the membrane properties of the sustentacular cells associated with secretion by using intracellular recording techniques, c. to document the release of secretory material in these cells using microscopic techniques, d. to study the coupling between adjacent sustentacular cells by the intracellular injection of fluorescent dyes and e. to investigate the uptake and distribution of intranasally and intravascularly injected fluorochromes by the sustentacular cells. The results of the proposed experiments will form the experimental basis on which to relate perireceptor processes to the activity of the receptor neurons, to studies of the coding of odor quality and to clinical trials of drug treatment for peripheral rhinitis.